Polarization Reversal and Ferroelectric Domain Structure Observed in Electroded Cesium Dihydrogen Phosphate Crystals Using an X-Ray Anomalous Dispersion Effect

抄録

We have carried out an X-ray intensity measurement and X-ray topography on electroded b plates of ferroelectric cesium dihydrogen phosphate, CsH₂PO₄ (CDP), using a synchrotron radiation with a wavelength of 2.482, Å above the Cs L₃-absorption edge. We have found that integrated intensities I(150) and I(\macr{1}\macr{5}0) show an anomalously large breakdown of Friedel's law, I(150)/I(\marc{1}\macr{5}0)=10.4 at 125, K, and display a ferroelectric hysteresis loop. The hysteresis loop determines that spontaneous polarization is antiparallel to the b axes set in both ferroelectric crystal structures related by inversions. The (150) diffraction topography shows that a single domain turns into a lamellar domain structure without fractal aspects after short-circuiting the b plate. The atomic displacement associated with polarization reversal is shown in a crystal structure model of 180° domains observed in the X-ray topograph.